1. Field of the Invention
The present invention is directed to an alignment sensing device for use in an apparatus in which the proper alignment of an article in relation to the apparatus may be sensed prior to activation of the apparatus and, further, to prevent the activation of the apparatus in the event that the article is improperly aligned or not present.
2. Description of the Prior Art
In the apparatus disclosed in my U.S. Pat. No. 4,598,570, electrical terminals to be crimped are fed in step-by-step movement to the apparatus. The terminals are integrally attached at one end to an elongate carrier strip, each step of movement of the carrier strip advancing a terminal into position on a stationary anvil of the crimping apparatus. The anvil is formed with a flat front surface lying in a general vertical plane and a vertically movable cutter element slides in face-to-face engagement with the front surface of the anvil. The face of the cutter engaged with the anvil is formed with a horizontal slot which slidably receives the carrier strip to position the terminal relative to the anvil and, in a normally maintained rest position, to guide the terminal onto the upper surface of the anvil. A vertically movable die assembly is mounted on the anvil and a terminal is advanced to the anvil by driving the carrier strip forward while the die assembly is in a raised position. When the terminal is located on the anvil, a wire is moved into alignment with the terminal and the die assembly is driven downward to perform the crimping operation. During this downward movement of the die assembly, the die assembly engages the cutter and drives the cutter downward. The carrier strip is trapped within the horizontal slot in the cutter, and downward movement of the cutter shears the terminal on the anvil from the carrier strip along the plane of engagement between the cutter and the vertical front face of the anvil. The die assembly is then raised and the cycle is repeated.
In the apparatus disclosed in a U.S. Pat. No. 4,654,952, a wire locater assembly for use in the crimping apparatus of the type referred to above is disclosed, in which the wire may be gripped by the locater closely adjacent the front vertical surface of the anvil so that the only portion of the wire not supported by the locater is that which vertically overlies the terminal.
In order to produce a satisfactory mechanical and electrical connection between the wire and the terminal, both the wire and the terminal must be accurately positioned so that the wire is centered between the opposed legs of the U-shaped section immediately prior to the crimping of the legs onto the wire. Accurate placement of the terminal also protects the die assembly from being damaged by attempting to crimp a terminal which is improperly aligned. The use of an elongate carrier strip to advance terminals into position on the stationary anvil of the crimping apparatus does not ensure proper alignment of the terminal on the anvil, since prior to being fed into position on the crimping apparatus, the terminal may have been bent out of alignment at the relatively short neck portion extending from the end of the U-shaped portion to the adjacent edge of the carrier strip. Furthermore, the trend toward miniaturization of electric circuitry and circuit elements has resulted in the usage of increasingly smaller terminals and relatively small or fine wires. The reduction in size of the terminal itself increases the degree of precision required to accurately align the wire and the terminal.